Why do the lights go out on trains?

Question

I'm a regular commuter on NJ Tranist and at least twice on the ride into Manhattan the lights and either air conditioner or heater go out all of a sudden. It always happens in the same area.

Is there a particular reason for this? I once heard a conductor muttering something about a "phase change," but have no idea what that means either. Does it have something to do with NJT trains moving into Amtrak territory?

Just curious.

Answer 1

a ghost in the machine maybe

Answer 2

Most subway trains get their power from the rails.

Each owning company pays for the power they use.

So if your changing territorys between suppliers then for a split

second the train loses power until it rolls into the new suppliers

rails.. so for that split second the train is coasting and not being

supplied with ANY power at all.

Answer 3

That sounds creepy....I would never go on a boat or train in my life because Im too scared.

Answer 4

as said in other posts there is a break in the third rail this can happen in tunnels or above ground like in chicago on the brown line where the el passes a grade crossing and the lights do go out but come back on nothing to worry about its just normal operation if something went wrong than the engineer would alert everyone in the cars what to do and how to evacuate if needed

Answer 5

That would be a phase break. Its a gap in the wires between a section at a different Hz. For instance, 25,000vAC 60Hz transitioning into 25,000vAC 25Hz - there has to be a gap of course.

Answer 6

It is called a phase gap.  A previous answer described it very well.  

Engineers are alerted to the location of a phase gap by signs along the way.  They must disconnect from the power source before crossing the gap, reset the systems for the new power source (some trains do this automatically), then reconnect on the other side.

Answer 7

plug comes out, and someone has to go plug it back in

Answer 8

Maybe it needed another 10 cents in the meter!